"It will cost more to modify it than it would cost to buy a hobby grade"
Nope! Good quality hobby grade parts can now be had for cheap. You can get a decent esc for £10, a servo for £2.79, a 2.4ghz receiver for £3.79. Be sure to ask these people where you can find a hobby grade car for under £17!
"They are weak and the gears won't handle extra power"
This is sometimes true if you're talking about modern cheap crap like New Bright but it couldn't be more wrong when it comes to classic toy grade stuff. In particular, stuff made by Nikko has very good build quality and strong gears. Some Nikko gearboxes are even direct clones of Tamiya designs, the F10 buggy and all of the rebadged versions (such as the Radio Shack Golden Arrow) have the same gearbox as the Tamiya Grasshopper, a gearbox which is famous for being bullet proof, the F10 even goes one step further and uses metal diff gears vs plastic for the Tamiya. The Hawg/Thor series, the Scorpion series and the Dictator series also feature incredibly strong gearboxes that will even handle brushless power with ease.
"Nikko/Radio Shack etc is pure toy grade crap"
Again, this usually comes from someone with absolutely ZERO knowledge of what they are talking about. For starters, Nikko stuff is usually exceptionally well made and strong but furthermore some of their stuff could easily be classed as hobby grade, it just happens to be that it was mass produced in a factory.
Take the Nikko Hawg, a 1/10 scale monster truck with twin 380 motors, twin gearboxes and dual link suspension up front. The truck can be fully ballraced, the wheels come off with a traditional mini spanner and at the time of it's release there was a full range of spare parts available to buy.
What many of these people don't realise is that Nikko had a special division that was tasked with creating these more advanced models that met or even exceeded many contemporary hobby grade vehicles. The F10 series of buggies was a Grasshopper clone but with better front suspension. The Dictator was like a buggy equivalent to the Hawg. Twin 380 motors, double wishbone suspension front AND rear, mental dog bone drive shafts, front and rear differentials and it could be fitted with ball bearings literally everywhere, the Tamiya hornet couldn't dream of matching that specifcation. Nikko even went on to produce full hobby grade, belt driven 4x4 buggies and even a Nitro touring car. One thing is for certain, Nikko knew how to make good vehicles with massive potential!
The story is similar with Radio Shack, many of their vehicles were just rebadged Nikko products and then you had stuff from other suppliers like the Red Arrow, a buggy that would kick a Grasshoppers ass and give a Hornet a run for it's money, nothing toy grade about it! Radio Shack also outsourced to the same company who made the Tamiya QD range of RTR vehicles. It's a well known fact that the QD version of the Tamiya monster Beetle has a much stronger gearbox than it's larger "hobby grade" brother. If you look on youtube you'll see several videos of the QD beetle bombing around with brushless power. What many don't realise is that there are 6 or 7 Radio Shack models that feature the exact same chassis and gearbox so they can handle brushless power too!There is also a new breed of RC coming out of China, you can now get stuff at a bargain price that is made from high quality plastics, not the horrible brittle stuff that was once synonymous with Chinese toys. You can buy lipo powered 4x4 fully ballraced trucks for £50 these days and you'll still fine a queue of people waiting to tell you how they are toy grade and not hobby grade despite being infinitely more powerful and more sophisticated than many entry level offerings from the established hobby brands
"AA batteries are useless"
This is another case of startling ignorance, NIMH AA batteries have come on a LONG way. 8 months back when I was new to things I asked about upgrading the motor in my Nikko boat and got this repsonse: "AA cells will be at or near their limit running the existing motor"
It's important to note just how bad this advice is, it's completely untrue and just made up on the spot but worse still it's incredibly inaccurate and far from reality.
The stock motor in the boat barely draws 1 amp under load, Eneloop pros can sustain up to 10amps or more. There really is a lot of bad advice being handed out in discussion forums all over the internet. It's a shame people don't stick to giving advice about things they are familiar with!
You wouldn't want to try running a 540 motor from AA batteries (although I've done it with a 27t silver can!) but anything 280 size, most 380 size motors and even some smaller brushless motors will run fine from Sanyo Eneloop cells, especially the Pro versions.
I've even seen people talk a guy into picking up a dremel and cutting out the stock 8 cell tray in his car so he could fit a "real pack" the real pack was made of 8 1600mah AA cells. He could have just kept his car intact and fitted 8 2450mah Eneloops that would last much longer and probably had a better discharge rating than the pack he bought!
"It will never be as good as car X even if you mod it"
And this is probably one of the ones you hear the most. In a hobby that revolves around tinkering why do some people not realise that sometimes you don't do things out of logic but because it's fun!? You don't mod a toy grade to try and make it compete with some other hobby grade car (although it's possible sometimes) you do it because it's fun to make that individual car better and more fun. Comparisons to other cars is completely irrelevant and misses the point.
You'll always face snobbery in this hobby and toy grade stuff is an easy target for people who feel the need to justify the fact they spent £1000 on a car, especially when they see you having fun with something you got on ebay for £10!
